Interaction c.v. Cabernet Franc/ terroir in northeastern Italy

Site evaluation and selection to optimize wine quality in Europe has been a long-term goal of vine scientists seeking to adapt to new production strategies. Denominazione di Origine Controllata (DOC) in viticulture is based on natural environmental conditions and on ‘terroir’. Organoleptic characteristics typical of Cabernet Franc were researched because in the past the variety was often confused with Carmenère. The present trial was carried out in order to study its typical characteristics. During the period, 1997-2001, eight different clones of Cabernet Franc were tested in two viticultural areas of Northeastern Italy (Friuli Venezia Giulia and Trentino Alto Adige). The eight clones examined were from French selections (210, 212, 214, 312, 327, 331, 394, and 623). The following quantitative and qualitative parameters were collected annually at harvest: number of buds, number of grapes, bud fertility, yield/vine, sugar content (°Brix), titratable acidity, pH. During winter, pruning wood was measured. Data collected were standardized for removing the "year effect" and were submitted to Analysis of Variance (ANOVA) using the Student-Newman-Keules SNK method for mean separation. They were also analyzed with Wricke's eco-valence using program S116 (Statistical Reasearch Program Librarian Agriculture - Canada). This allowed definition of clonal properties and underlined the factor that different microclimatic conditions are very important in determining grape quality. The two viticultural regions showed great variability in vine behavior and vine balance. In particular, Friuli Venezia Giulia showed vines with less vigor, lower yield and less sugar accumulation than those of Trentino Alto Adige. Among clonal selections under observation, clone 623 demonstrated the highest yield and cluster weight and adequate sugar content. The Wricke test showed that French selections were highly stable depending on the 'terroir'.